Transit Systems, Network Planning, Walking and Active Mobility

Learning objectives

Learn to characterize the mechanisms, assumptions and observational evidence connecting public transport capacity, frequency and reliability, transit travel times and stop spacing, pedestrian crossing and accessible design, bicycle networks and multimodal safety. Demonstrate unit consistency, interpret safety and access alongside vehicle throughput, and compare model predictions against field observations before making recommendations.

How to study this unit

Work through all four lessons, reproduce each numerical illustration without copying the result, operate the linked investigations, then answer the unit assessment and prepare a short project memo. Recognize which assumptions are useful for learning and which prevent design decisions.

Lesson 7.1: Public transport capacity, frequency and reliability

Physical and planning meaning

Service frequency and vehicle capacity determine nominal passenger-carrying ability, but dwell times, congestion and schedule variation affect delivered service. A bus corridor carrying fewer vehicles can move more people than a general traffic lane. Passenger volume measures access differently from traffic throughput.

Governing relationship

Directional passenger capacity = vehicles/hour × usable passengers/vehicle.

Interpreted worked case

A bus route with one bus every eight minutes offers 7.5 buses per hour. At 60 usable passengers per bus, nominal directional capacity is 450 passengers/h. Actual boardings depend on travel patterns and stop loads.

Investigating an assumption

Compare strategies of longer vehicles, higher frequency and transit priority for a crowded route with unreliable operation.

Important limitations

Nominal capacity does not equal passenger demand; safety limits, access at stops and bus bunching constrain deployment.

Measurement protocol

Specify which observations distinguish the proposed engineering relationship from a coincidental correlation. Record station location, observation interval, vehicles or users included, calibration checks and missing data. A correct equation evaluated on a biased dataset can create a less defensible conclusion than a rough estimate accompanied by an explicit uncertainty interval.

Three distinct evidence-based investigations

Investigation 7.1.1

An agency is reviewing a school frontage where crossing demand varies sharply during arrival and dismissal. The primary affected users include students and caregivers. Before transferring the relationship Directional passenger capacity = vehicles/hour × usable passengers/vehicle. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for crossing delay, visibility and conflict; compare that baseline with an alternative centred on speed management and a protected walking route. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.1.2

Use this worked reference as a challenge rather than as a template to memorize: A bus route with one bus every eight minutes offers 7.5 buses per hour. At 60 usable passengers per bus, nominal directional capacity is 450 passengers/h. Actual boardings depend on travel patterns and stop loads. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.1.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Nominal capacity does not equal passenger demand; safety limits, access at stops and bus bunching constrain deployment. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of public transport capacity, frequency and reliability. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (Directional passenger capacity = vehicles/hour × usable passengers/vehicle.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about public transport capacity, frequency and reliability, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Lesson 7.2: Transit travel times and stop spacing

Physical and planning meaning

Stop spacing trades accessibility against running time. Close stops shorten walking distances but add acceleration, braking and passenger dwell penalties. Bus travel time combines cruise time, stop dwell, signal delay and stochastic congestion. End-to-end speed can be much lower than cruise speed.

Governing relationship

T = L/v_run + N(t_dwell+t_accel) + t_delay for an approximate service segment.

Interpreted worked case

A 6 km bus segment at moving speed 30 km/h takes 12 minutes before stops. If ten stops add 25 s dwell and 10 s acceleration delay each, stop penalties add 5.83 minutes, excluding traffic signals.

Investigating an assumption

Why may a stop-spacing improvement help average journey times yet harm travelers who cannot walk long distances?

Important limitations

Assuming every scheduled stop is used or every bus experiences the same delay may overestimate or underestimate real service.

Dimensional audit

Before computing, rewrite every quantity in one coherent system of units. A time rate needs a time denominator; a spatial density needs a road-length denominator; a percentage must become a decimal before entering an algebraic equation. Unit checking can reject many plausible-looking but incorrect answers without any specialist software.

Three distinct evidence-based investigations

Investigation 7.2.1

An agency is reviewing a low-lying corridor with intermittent drainage blockage after intense storms. The primary affected users include commuters, merchants and emergency responders. Before transferring the relationship T = L/v_run + N(t_dwell+t_accel) + t_delay for an approximate service segment. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for flooded travel lanes and unreliable service; compare that baseline with an alternative centred on drainage maintenance plus a safe diversion strategy. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.2.2

Use this worked reference as a challenge rather than as a template to memorize: A 6 km bus segment at moving speed 30 km/h takes 12 minutes before stops. If ten stops add 25 s dwell and 10 s acceleration delay each, stop penalties add 5.83 minutes, excluding traffic signals. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.2.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Assuming every scheduled stop is used or every bus experiences the same delay may overestimate or underestimate real service. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of transit travel times and stop spacing. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (T = L/v_run + N(t_dwell+t_accel) + t_delay for an approximate service segment.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about transit travel times and stop spacing, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Lesson 7.3: Pedestrian crossing and accessible design

Physical and planning meaning

Pedestrian crossing performance depends on walking distance, waiting time, visibility, physical accessibility and conflict exposure. A fixed clearance interval derived from a single walking speed may fail to accommodate users with limited mobility. Curb ramps, tactile guidance and continuous paths are integral rather than optional.

Governing relationship

Illustrative crossing time = width / walking speed.

Interpreted worked case

At a crossing width of 18 m and a walking speed of 1.0 m/s, movement time is 18 s. This excludes start-up time and any additional jurisdictional requirements for clearance and accessibility.

Investigating an assumption

How would an accessible refuge island change the geometry and risk of a wide crossing where vehicle volumes are heavy?

Important limitations

Do not use this division alone to set legal signal clearance intervals; follow the adopted traffic-control and accessibility standards.

Alternative design comparison

Compare at least two interventions against the same baseline. Record whether each changes demand, available capacity, exposure, pavement condition, human behavior or monitoring quality. An alternative with the largest improvement in one performance indicator is not necessarily superior when its cost, emissions, access impacts and failure modes are considered.

Three distinct evidence-based investigations

Investigation 7.3.1

An agency is reviewing a bridge rehabilitation requiring temporary lane closures. The primary affected users include construction teams and road users. Before transferring the relationship Illustrative crossing time = width / walking speed. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for unexpected queues and disrupted access; compare that baseline with an alternative centred on staged works and active travel-time messaging. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.3.2

Use this worked reference as a challenge rather than as a template to memorize: At a crossing width of 18 m and a walking speed of 1.0 m/s, movement time is 18 s. This excludes start-up time and any additional jurisdictional requirements for clearance and accessibility. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.3.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Do not use this division alone to set legal signal clearance intervals; follow the adopted traffic-control and accessibility standards. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of pedestrian crossing and accessible design. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (Illustrative crossing time = width / walking speed.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about pedestrian crossing and accessible design, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Lesson 7.4: Bicycle networks and multimodal safety

Physical and planning meaning

A cycling network requires route continuity, safe conflict management and usable intersections, not isolated short segments. Separation, speed management, crossing design and maintenance influence comfort and safety. Network completeness can be a stronger accessibility measure than a single facility width.

Governing relationship

Bicycle trip time T = route length/mean moving speed plus intersection delay.

Interpreted worked case

A 4.5 km protected bicycle route traveled at 15 km/h requires 18 minutes moving time. Five crossings averaging 20 s of delay add about 1.67 minutes. The route may still outperform a shorter but dangerous network gap.

Investigating an assumption

Compare perceived safety and actual conflict exposure across protected lanes, shared streets and painted lanes with similar geometric widths.

Important limitations

Travel times alone are insufficient to evaluate mode choice; intersection quality and personal security matter.

Sensitivity and uncertainty

Vary one uncertain parameter while keeping others fixed, then vary a second parameter jointly. A steep response indicates that the result should be reported as a range rather than a single number. Do not equate a sensitivity exercise with a statistical confidence interval; uncertainty also includes model structure and measurement bias.

Three distinct evidence-based investigations

Investigation 7.4.1

An agency is reviewing an industrial connection used by large goods vehicles and irregular delivery convoys. The primary affected users include truck drivers and nearby residents. Before transferring the relationship Bicycle trip time T = route length/mean moving speed plus intersection delay. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for reliable travel time, pavement damage and turning geometry; compare that baseline with an alternative centred on a freight-access management plan. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.4.2

Use this worked reference as a challenge rather than as a template to memorize: A 4.5 km protected bicycle route traveled at 15 km/h requires 18 minutes moving time. Five crossings averaging 20 s of delay add about 1.67 minutes. The route may still outperform a shorter but dangerous network gap. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.4.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Travel times alone are insufficient to evaluate mode choice; intersection quality and personal security matter. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of bicycle networks and multimodal safety. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (Bicycle trip time T = route length/mean moving speed plus intersection delay.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about bicycle networks and multimodal safety, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Unit synthesis exercise

Connect public transport capacity, frequency and reliability with bicycle networks and multimodal safety: imagine a corridor proposal that improves the first measure but worsens the last. Write a one-page recommendation showing the trade-off, a minimum dataset for testing both effects, and the circumstances that would reverse your recommendation.

Reading the laboratory outputs

Every chart is calculated for hypothetical parameters. Change one parameter at a time to understand the model. Check a point by hand. Export a CSV, note the axes, then identify at least one physically relevant effect omitted by the model. No laboratory in this book is approved for design or real-time operational control.

Extended public transport case: frequency, accessibility and person throughput

A metropolitan bus route is overcrowded in the morning while general traffic lanes operate below their apparent vehicle capacity. A proposal to widen the road may produce additional private vehicle space without materially increasing access for people who depend on buses. Begin by defining the decision metric. Travel time, passenger throughput, wait-time reliability, access to stops and affordability are different outcomes. Treat the bus network as a service with schedules and passenger flows rather than an undifferentiated vehicle stream.

Suppose the nominal bus headway is eight minutes, implying 60/8=7.5 scheduled vehicles per hour. With practical usable capacity sixty people per bus, the nominal passenger-carrying capacity is 450 passengers per hour per direction. That does not mean the route actually carries 450 passengers: some trips may be partly empty and crowded demand may cluster in short periods. The same average headway can also conceal irregular dispatch. If two buses arrive together followed by a sixteen-minute gap, average passenger wait increases for random arrivals even though the mean number of buses per hour has not changed. Reliability requires observations of the actual headway distribution.

A simple run-time study can be constructed for a six-kilometre service segment moving at 30 km/h between stops. Base running time is twelve minutes. Ten stopping events adding a combined 35 seconds each for dwell and acceleration would add 350 seconds, or about 5.83 minutes, before signal delay. But removing every other stop is not necessarily a good intervention. Passengers with reduced mobility, school children and older residents may face longer walking distances. A more complete evaluation compares total door-to-door journey time rather than in-vehicle time alone.

Examine a junction where buses are delayed by turning traffic. Possibilities include queue-jump lanes, transit signal priority, curbside loading enforcement and relocating bus stops. A queue-jump lane may need to take space from a general traffic lane; signal priority must be assessed for its impacts on crossing pedestrians and other directions. An unsafe crossing at the new stop can offset a small improvement in bus travel time. Collect observed boarding profiles, bus occupancy, headway adherence, stop dwell time and crossing delay before selecting a treatment.

The pedestrian investigation should include accessible walking conditions. At 1.0 m/s an eighteen-metre crossing takes eighteen seconds of moving time; that alone is not an adequate signal timing design. Start-up, speed variation, refuge islands, pedestrian traffic and adopted clearance standards affect the requirement. Examine whether a protected crossing, narrower crossing distance or refuge creates more benefit than a short signal-timing adjustment. Conduct disability-aware consultation rather than relying on a single nominal walking speed.

Conclude with an integrated comparison among increasing frequency, using larger buses, improving priority, revising stop spacing and reallocating road space. Report annualized cost, estimated person-hours saved, reliability, accessibility, emissions and construction disruption as distinct measures. A proposal driven solely by maximum bus capacity can fail if service demand, operator capacity, finance or stop geometry are not validated.

Unit 7: Transit, Walking and Cycling

Book 14 · Transportation Engineering · Civil Engineering

Learning objectives

Learn to characterize the mechanisms, assumptions and observational evidence connecting public transport capacity, frequency and reliability, transit travel times and stop spacing, pedestrian crossing and accessible design, bicycle networks and multimodal safety. Demonstrate unit consistency, interpret safety and access alongside vehicle throughput, and compare model predictions against field observations before making recommendations.

How to study this unit

Work through all four lessons, reproduce each numerical illustration without copying the result, operate the linked investigations, then answer the unit assessment and prepare a short project memo. Recognize which assumptions are useful for learning and which prevent design decisions.

Lesson 7.1: Public transport capacity, frequency and reliability

Physical and planning meaning

Service frequency and vehicle capacity determine nominal passenger-carrying ability, but dwell times, congestion and schedule variation affect delivered service. A bus corridor carrying fewer vehicles can move more people than a general traffic lane. Passenger volume measures access differently from traffic throughput.

Governing relationship

Directional passenger capacity = vehicles/hour × usable passengers/vehicle.

Interpreted worked case

A bus route with one bus every eight minutes offers 7.5 buses per hour. At 60 usable passengers per bus, nominal directional capacity is 450 passengers/h. Actual boardings depend on travel patterns and stop loads.

Investigating an assumption

Compare strategies of longer vehicles, higher frequency and transit priority for a crowded route with unreliable operation.

Important limitations

Nominal capacity does not equal passenger demand; safety limits, access at stops and bus bunching constrain deployment.

Measurement protocol

Specify which observations distinguish the proposed engineering relationship from a coincidental correlation. Record station location, observation interval, vehicles or users included, calibration checks and missing data. A correct equation evaluated on a biased dataset can create a less defensible conclusion than a rough estimate accompanied by an explicit uncertainty interval.

Three distinct evidence-based investigations

Investigation 7.1.1

An agency is reviewing a school frontage where crossing demand varies sharply during arrival and dismissal. The primary affected users include students and caregivers. Before transferring the relationship Directional passenger capacity = vehicles/hour × usable passengers/vehicle. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for crossing delay, visibility and conflict; compare that baseline with an alternative centred on speed management and a protected walking route. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.1.2

Use this worked reference as a challenge rather than as a template to memorize: A bus route with one bus every eight minutes offers 7.5 buses per hour. At 60 usable passengers per bus, nominal directional capacity is 450 passengers/h. Actual boardings depend on travel patterns and stop loads. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.1.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Nominal capacity does not equal passenger demand; safety limits, access at stops and bus bunching constrain deployment. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of public transport capacity, frequency and reliability. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (Directional passenger capacity = vehicles/hour × usable passengers/vehicle.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about public transport capacity, frequency and reliability, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Lesson 7.2: Transit travel times and stop spacing

Physical and planning meaning

Stop spacing trades accessibility against running time. Close stops shorten walking distances but add acceleration, braking and passenger dwell penalties. Bus travel time combines cruise time, stop dwell, signal delay and stochastic congestion. End-to-end speed can be much lower than cruise speed.

Governing relationship

T = L/v_run + N(t_dwell+t_accel) + t_delay for an approximate service segment.

Interpreted worked case

A 6 km bus segment at moving speed 30 km/h takes 12 minutes before stops. If ten stops add 25 s dwell and 10 s acceleration delay each, stop penalties add 5.83 minutes, excluding traffic signals.

Investigating an assumption

Why may a stop-spacing improvement help average journey times yet harm travelers who cannot walk long distances?

Important limitations

Assuming every scheduled stop is used or every bus experiences the same delay may overestimate or underestimate real service.

Dimensional audit

Before computing, rewrite every quantity in one coherent system of units. A time rate needs a time denominator; a spatial density needs a road-length denominator; a percentage must become a decimal before entering an algebraic equation. Unit checking can reject many plausible-looking but incorrect answers without any specialist software.

Three distinct evidence-based investigations

Investigation 7.2.1

An agency is reviewing a low-lying corridor with intermittent drainage blockage after intense storms. The primary affected users include commuters, merchants and emergency responders. Before transferring the relationship T = L/v_run + N(t_dwell+t_accel) + t_delay for an approximate service segment. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for flooded travel lanes and unreliable service; compare that baseline with an alternative centred on drainage maintenance plus a safe diversion strategy. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.2.2

Use this worked reference as a challenge rather than as a template to memorize: A 6 km bus segment at moving speed 30 km/h takes 12 minutes before stops. If ten stops add 25 s dwell and 10 s acceleration delay each, stop penalties add 5.83 minutes, excluding traffic signals. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.2.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Assuming every scheduled stop is used or every bus experiences the same delay may overestimate or underestimate real service. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of transit travel times and stop spacing. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (T = L/v_run + N(t_dwell+t_accel) + t_delay for an approximate service segment.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about transit travel times and stop spacing, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Lesson 7.3: Pedestrian crossing and accessible design

Physical and planning meaning

Pedestrian crossing performance depends on walking distance, waiting time, visibility, physical accessibility and conflict exposure. A fixed clearance interval derived from a single walking speed may fail to accommodate users with limited mobility. Curb ramps, tactile guidance and continuous paths are integral rather than optional.

Governing relationship

Illustrative crossing time = width / walking speed.

Interpreted worked case

At a crossing width of 18 m and a walking speed of 1.0 m/s, movement time is 18 s. This excludes start-up time and any additional jurisdictional requirements for clearance and accessibility.

Investigating an assumption

How would an accessible refuge island change the geometry and risk of a wide crossing where vehicle volumes are heavy?

Important limitations

Do not use this division alone to set legal signal clearance intervals; follow the adopted traffic-control and accessibility standards.

Alternative design comparison

Compare at least two interventions against the same baseline. Record whether each changes demand, available capacity, exposure, pavement condition, human behavior or monitoring quality. An alternative with the largest improvement in one performance indicator is not necessarily superior when its cost, emissions, access impacts and failure modes are considered.

Three distinct evidence-based investigations

Investigation 7.3.1

An agency is reviewing a bridge rehabilitation requiring temporary lane closures. The primary affected users include construction teams and road users. Before transferring the relationship Illustrative crossing time = width / walking speed. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for unexpected queues and disrupted access; compare that baseline with an alternative centred on staged works and active travel-time messaging. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.3.2

Use this worked reference as a challenge rather than as a template to memorize: At a crossing width of 18 m and a walking speed of 1.0 m/s, movement time is 18 s. This excludes start-up time and any additional jurisdictional requirements for clearance and accessibility. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.3.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Do not use this division alone to set legal signal clearance intervals; follow the adopted traffic-control and accessibility standards. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of pedestrian crossing and accessible design. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (Illustrative crossing time = width / walking speed.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about pedestrian crossing and accessible design, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Lesson 7.4: Bicycle networks and multimodal safety

Physical and planning meaning

A cycling network requires route continuity, safe conflict management and usable intersections, not isolated short segments. Separation, speed management, crossing design and maintenance influence comfort and safety. Network completeness can be a stronger accessibility measure than a single facility width.

Governing relationship

Bicycle trip time T = route length/mean moving speed plus intersection delay.

Interpreted worked case

A 4.5 km protected bicycle route traveled at 15 km/h requires 18 minutes moving time. Five crossings averaging 20 s of delay add about 1.67 minutes. The route may still outperform a shorter but dangerous network gap.

Investigating an assumption

Compare perceived safety and actual conflict exposure across protected lanes, shared streets and painted lanes with similar geometric widths.

Important limitations

Travel times alone are insufficient to evaluate mode choice; intersection quality and personal security matter.

Sensitivity and uncertainty

Vary one uncertain parameter while keeping others fixed, then vary a second parameter jointly. A steep response indicates that the result should be reported as a range rather than a single number. Do not equate a sensitivity exercise with a statistical confidence interval; uncertainty also includes model structure and measurement bias.

Three distinct evidence-based investigations

Investigation 7.4.1

An agency is reviewing an industrial connection used by large goods vehicles and irregular delivery convoys. The primary affected users include truck drivers and nearby residents. Before transferring the relationship Bicycle trip time T = route length/mean moving speed plus intersection delay. to the location, explain which inputs could be directly observed, which would need a proxy, and which are not meaningful without a local policy or design standard. Establish a baseline for reliable travel time, pavement damage and turning geometry; compare that baseline with an alternative centred on a freight-access management plan. Your written answer must separate improvements that follow from a formula from improvements that are only plausible hypotheses. Address conditions in which the intervention would fail.

Investigation 7.4.2

Use this worked reference as a challenge rather than as a template to memorize: A 4.5 km protected bicycle route traveled at 15 km/h requires 18 minutes moving time. Five crossings averaging 20 s of delay add about 1.67 minutes. The route may still outperform a shorter but dangerous network gap. Replace one input with a plausible field observation, state why the replacement is plausible, and predict the direction of the result before computing. If the prediction differs from the calculation, investigate units and the sign convention first. Explain how uncertainty from measurement, behavior and a simplified model affects the credibility of a precise numerical answer.

Investigation 7.4.3

A project manager proposes to use a single number from this topic to approve an investment. Prepare a critique rooted in the following limitation: Travel times alone are insufficient to evaluate mode choice; intersection quality and personal security matter. List two measurements that would improve the study, one externality that the calculation does not represent and one practical decision that could be deferred until the missing evidence is obtained. Avoid claiming the educational model has been professionally calibrated or validated on a real transportation network.

Explain the computation to a classmate

Without looking at the numerical illustration, reconstruct the logic of bicycle networks and multimodal safety. Start with the field measurement and unit definition, define the reference condition, state the idealization in the equation (Bicycle trip time T = route length/mean moving speed plus intersection delay.), and then walk through the calculation so that a reader can independently check every value. Identify which result can be checked by a second technique. If observations contradict the simple model, explain how you would revise the model rather than discard the observations.

Field data and reporting protocol

For a short field exercise about bicycle networks and multimodal safety, specify a time window, observation location, data dictionary and recording method. Protect individual privacy by avoiding unnecessary vehicle or personal identifiers. Use at least three quality checks: plausibility ranges for the raw input, missing-value counts, and a reconciliation of any aggregated totals. Present separate notes on systematic bias, day-to-day variability and uncertainty in the equation itself.

Decision boundary

The relationship in this lesson is appropriate for concept exploration and transparent back-of-the-envelope screening. A code-compliant transportation-system decision would additionally need jurisdiction-specific requirements, evidence of relevant site conditions and a documented professional review. Name the exact assumptions that would need replacement and identify stakeholders who might be excluded if the decision were made entirely from a vehicle-centred metric.

Unit synthesis exercise

Connect public transport capacity, frequency and reliability with bicycle networks and multimodal safety: imagine a corridor proposal that improves the first measure but worsens the last. Write a one-page recommendation showing the trade-off, a minimum dataset for testing both effects, and the circumstances that would reverse your recommendation.

Reading the laboratory outputs

Every chart is calculated for hypothetical parameters. Change one parameter at a time to understand the model. Check a point by hand. Export a CSV, note the axes, then identify at least one physically relevant effect omitted by the model. No laboratory in this book is approved for design or real-time operational control.

Extended public transport case: frequency, accessibility and person throughput

A metropolitan bus route is overcrowded in the morning while general traffic lanes operate below their apparent vehicle capacity. A proposal to widen the road may produce additional private vehicle space without materially increasing access for people who depend on buses. Begin by defining the decision metric. Travel time, passenger throughput, wait-time reliability, access to stops and affordability are different outcomes. Treat the bus network as a service with schedules and passenger flows rather than an undifferentiated vehicle stream.

Suppose the nominal bus headway is eight minutes, implying 60/8=7.5 scheduled vehicles per hour. With practical usable capacity sixty people per bus, the nominal passenger-carrying capacity is 450 passengers per hour per direction. That does not mean the route actually carries 450 passengers: some trips may be partly empty and crowded demand may cluster in short periods. The same average headway can also conceal irregular dispatch. If two buses arrive together followed by a sixteen-minute gap, average passenger wait increases for random arrivals even though the mean number of buses per hour has not changed. Reliability requires observations of the actual headway distribution.

A simple run-time study can be constructed for a six-kilometre service segment moving at 30 km/h between stops. Base running time is twelve minutes. Ten stopping events adding a combined 35 seconds each for dwell and acceleration would add 350 seconds, or about 5.83 minutes, before signal delay. But removing every other stop is not necessarily a good intervention. Passengers with reduced mobility, school children and older residents may face longer walking distances. A more complete evaluation compares total door-to-door journey time rather than in-vehicle time alone.

Examine a junction where buses are delayed by turning traffic. Possibilities include queue-jump lanes, transit signal priority, curbside loading enforcement and relocating bus stops. A queue-jump lane may need to take space from a general traffic lane; signal priority must be assessed for its impacts on crossing pedestrians and other directions. An unsafe crossing at the new stop can offset a small improvement in bus travel time. Collect observed boarding profiles, bus occupancy, headway adherence, stop dwell time and crossing delay before selecting a treatment.

The pedestrian investigation should include accessible walking conditions. At 1.0 m/s an eighteen-metre crossing takes eighteen seconds of moving time; that alone is not an adequate signal timing design. Start-up, speed variation, refuge islands, pedestrian traffic and adopted clearance standards affect the requirement. Examine whether a protected crossing, narrower crossing distance or refuge creates more benefit than a short signal-timing adjustment. Conduct disability-aware consultation rather than relying on a single nominal walking speed.

Conclude with an integrated comparison among increasing frequency, using larger buses, improving priority, revising stop spacing and reallocating road space. Report annualized cost, estimated person-hours saved, reliability, accessibility, emissions and construction disruption as distinct measures. A proposal driven solely by maximum bus capacity can fail if service demand, operator capacity, finance or stop geometry are not validated.